Method of forming a power module with a magnetic device having a conductive clip

Abstract

A method of forming a power module located on a conductive substrate by providing power conversion circuitry. The method of providing the power conversion circuitry includes forming a magnetic device by placing a magnetic core proximate a conductive substrate with a surface thereof facing a conductive substrate, and placing a conductive clip proximate a surface of the magnetic core. The method of forming the magnetic device also includes electrically coupling ends of the conductive clip to the conductive substrate to cooperatively form a winding therewith about the magnetic core. The method of providing the power conversion circuitry also includes providing at least one switch on the conductive substrate. The method of forming the power module also includes depositing an encapsulant about the power conversion circuitry.

What is claimed is: 
     
       1. A method of forming a power module located on a conductive substrate, comprising:
 providing power conversion circuitry, including:
 forming a magnetic device by:
 placing a magnetic core proximate said conductive substrate with a surface thereof facing said conductive substrate, 
 placing an entirely unencapsulated conductive clip having a bare horizontal lower surface facing and directly above a horizontal upper surface of said magnetic core, and 
 electrically coupling ends of said conductive clip to said conductive substrate to cooperatively form a winding therewith about said magnetic core, and 
 
 providing at least one switch on said conductive substrate; and 
 
 depositing an encapsulant about said power conversion circuitry. 
 
     
     
       2. The method as recited in  claim 1  wherein a lower surface of said magnetic core faces said conductive substrate. 
     
     
       3. The method as recited in  claim 1  wherein said conductive clip is about 8 to 12 mils in thickness. 
     
     
       4. The method as recited in  claim 1  wherein said conductive substrate is a leadframe. 
     
     
       5. The method as recited in  claim 1  further comprising adhering said magnetic core to said conductive substrate. 
     
     
       6. The method as recited in  claim 1  wherein said ends of said conductive clip are bent toward said conductive substrate about ends of said magnetic core. 
     
     
       7. The method as recited in  claim 1  further comprising soldering said conductive clip to said conductive substrate. 
     
     
       8. The method as recited in  claim 1  further comprising providing a gap between said conductive clip and said magnetic core. 
     
     
       9. The method as recited in  claim 1  further comprising forming terminals that protrude from sides and a lower surface of said power module. 
     
     
       10. The method as recited in  claim 1  wherein portions of said power module are formed from integrated circuits or surface mount components. 
     
     
       11. The method as recited in  claim 1  wherein said magnetic core is a single piece magnetic core. 
     
     
       12. The method as recited in  claim 1  wherein said ends of said conductive clip are surface mounted to said conductive substrate. 
     
     
       13. The method as recited in  claim 1  wherein said conductive clip spans an end-to-end length of said magnetic core. 
     
     
       14. A method of forming a power module located on a patterned, conductive leadframe, comprising:
 providing power conversion circuitry, including:
 forming a magnetic device by:
 adhering a magnetic core formed from a bar of magnetic material to said conductive leadframe, 
 locating at least one entirely unencapsulated conductive clip having a bare horizontal lower surface facing and directly above a horizontal upper surface of said magnetic core, 
 soldering ends of said at least one conductive clip to said conductive leadframe to cooperatively form a winding therewith about said magnetic core, and 
 
 
 providing at least one switch on said conductive leadframe; and 
 depositing an encapsulant about said power conversion circuitry. 
 
     
     
       15. The method as recited in  claim 14  wherein said bar of magnetic material is formed from manganese zinc ferrite. 
     
     
       16. The method as recited in  claim 14  further comprising forming terminals by creating leadframe fingers in said conductive leadframe that protrude from sides and a lower surface of said power module. 
     
     
       17. The method as recited in  claim 14  further comprising electrically coupling portions of said conductive leadframe with at least one wire bond. 
     
     
       18. The method as recited in  claim 14  wherein said ends of said at least one conductive clip are bent toward said conductive leadframe about ends of said magnetic core. 
     
     
       19. The method as recited in  claim 14  further comprising providing a gap between said magnetic core and said at least one conductive clip. 
     
     
       20. The method as recited in  claim 14  further comprising providing a gap between said magnetic core and said at least one conductive clip and further comprising substantially filling said gap with said encapsulant. 
     
     
       21. The method as recited in  claim 14  wherein said encapsulant is an epoxy encapsulant. 
     
     
       22. The method as recited in  claim 14  further comprising providing a controller and a driver. 
     
     
       23. The method as recited in  claim 14  wherein portions of said power module are formed from integrated circuits or surface mount components. 
     
     
       24. The method as recited in  claim 14  wherein said magnetic core is a single piece magnetic core. 
     
     
       25. The method as recited in  claim 14  wherein said ends of said at least one conductive clip are surface mounted to said conductive leadframe. 
     
     
       26. The method as recited in  claim 14  wherein said at least one conductive clip spans an end-to-end length of said magnetic core.